The document summarizes the results of three display advertising campaigns run by Udacity to promote enrollment in their Digital Marketing Nanodegree program. Campaign 1, targeting an affinity audience of business professionals and social media enthusiasts, performed best with a 33.2% ROI. Campaign 2 targeting digital marketing partners' sites had a lower ROI of 28.9%. Campaign 3 targeting the Nanodegree landing page itself achieved a 27.5% ROI. Recommendations include A/B testing creatives and headlines, expanding high-performing keywords, and including student reviews and offers to appeal to price-sensitive students.